Kramer



Aug. 11, 1959 FM x6 I VEN TOR.

ea wazzm K United States Patent IMPACT ELECTRIC SWITCH CONSTRUCTION Leo Kramer, Bensenvill'e, Ill., assignor, by mesne assignments, to Controls Company of America, Schiiler Park, Ill., a corporation of Delaware Application April '16, 1956, Serial No. 578,410

9 Claims. (Cl. 200-104 This invention relates to an impact electric switch construction and more particularly to an impact switch construction for fast contact closure without contact bounce. While the invention is disclosed in connection with a relay, it is useful with any means or mechanism for effecting quick and definite impact closure of electric contacts.

In closing electric contacts against each other by impact, as distinguished from sliding, difficulty is experienced in maintaining effective contact closure initially during closure because of the tendency of contact bounce. The sharp mpact of a contact against another contact gencrates relatively large reactive forces tending to reopen the contacts. This problem is present only at contact closure in high speed contact movement.

The present invention provides a simple mechanical construction which eliminates contact bounce. it is illustrated in connection with a single pole double throw switch forming part of a relay and in the form of the invention illustrated, a switch overlap action is provided in that one pair of contacts are closed before the other pair are opened. These single pole and contact overlap features are not essential. Instead, a multi-pole construction may readily be provided. It is also possible to have conventional contact action without overlap. Instead of a relay, any other means for actuating one or more movable contacts may be used.

For a more complete understanding of the invention, reference will now be made to the drawing wherein an exemplary embodiment is illustrated, it being understood that variations may be made within the scope of the claims.

Figure 1 is a plan view of a relay embodying the present invention.

Figures 2, 3 and 4 are side views of a relay embodying the present invention, the diflferent views showing different contact positions.

A relay comprises base member 10, preferably of ferro-magnetic material. Base member has upstanding arms 11 and 12. Carried by base member 10 in proximity to arm 11 is winding 14 around ferro-magnetic core 15 passing through the center of the winding. Core 15 is tight against base member 10 and has pole piece 16 for cooperation with armature 17 pivotally carried on the free edge of arm 11. Spring 19 extends between the free end of armature 17 and hook 20 punched out from arm 11. As is clearly illustrated, spring 19 biases armature 17 away from pole piece 16. Armature 17 carries movable spring contact arm 22 secured thereto in any desired manner. For example, movable contact arm 22 may be clamped between insulating blocks 23. Flexible lead wire 24 is provided for establishing an electrical connection to movable contact arm 22. It is possible to mount movable contact arm 22 directly upon armature 17 and ground the contact arm to the magnetic circuit of the relay. Movable contact arm 22 carries contact buttons 26 on opposite sides thereof at the free end of the contact arm.

Ann 12 has supporting portion 28 upon which is dis- Patented Aug. 11, 1959 posed contact stack 30. Contact stack 30 consists of two rigid insulating backing members 31 and 32 spaced from each other. Insulatingly supported in the contact stack are stationary spring contact arms 33 and 34. Stationary contact arms 33 and 34 have contact buttons at their free ends facing each other and adapted to cooperate with the contact buttons on the end of movable contact arm 22. Contact arms 33 and 34 are here illustrated as spaced apart so that normally the distance between their contact buttons is a bit less than the thickness of the contact buttons on movable arm 22. Figure 3 shows movable contact arm 22 so that contact will be made simultaneously with the contact buttons on arms 33 and 34. The spacing between insulating backing member 31 and contact spring arm 33 is sufficiently great so that in the position illustrated in Figure 2, the movable contact only engages the top contact. The same relationship is provided for bottom insulating backing member 32 and bottom contact arm 34, as shown in Figure 4. Contact arms 33 and 34 may have a greater space between them to eliminate contact overlap.

It is understood that contact arms 33 and 34 may have substantially greater flexibility than movable contact arm 22.

It is necessary that the movable contact arm be able to drive the stationary contact arm against the cooperating backing member. Thus the movable contact arm must be able to store sufficient energy to accomplish the above. Hence the flexibility of the movable and stationary contact arms is important.

Contact arms 33 and 34 are separated by insulator stop plate 36 disposed between these contact members. Thus, when the movable contact moves away from a stationary contact strip, insulator stop plate 36 prevents the stationary contact strip from following the movable contact strip beyond the center position illustrated in Figure 3. Preferably, each stationary contact arm is spring biased to bear against stop plate 36.

The various stationary contact arms may be insulatingly supported in the stack in any suitable fashion. Thus, as illustrated, bolts 39, cooperating with suitable insulating sleeves, pass through the parts of the stack and serve to maintain the assembly intact. Other means for maintaining the assembly in predetermined relationship may be used.

By having the movable contact arm store sufficient energy during operation the movable contact will engage the appropriate stationary contact and keep the engagement intact with the stationary contact arm being bent back until the cooperating backing member stops further flexing of the stationary contact arm. Hence the stationary contact arms must be sufficiently flexible to accomplish the above.

Various changes coming within the spirit of my invention may suggest themselves to those skilled in the art. Hence, I do not wish to be limited to the specific embodiments shown and described or uses mentioned, but intend the same to be merely exemplary, the scope of my invention being limited only by the appended claims.

What is claimed is:

1. An impact electric switch construction comprising at least one flexible stationary contact arm carrying a contact, a flexible movable contact arm carrying a contact and adapted to move said contact carried thereby in and out of contact with the contact on said stationary contact arm, means for limiting the flexure of the stationary arm in response to contact closure, and means for driving the movable arm sufliciently hard to flex the stationary arm to its limit and to hold said movable arm in contact with said stationary arm in flexed posi tion, the internal resilience of said flexible stationary contact arm providing the sole resistance to the movement of said movable contact arm until said means for limiting flexure becomes operative.

2. The construction according to claim 1 wherein said flexure limiting means comprises a relatively rigid arm for stopping the contact carrying portion of the stationary arm from excessive flexing.

3. The construction according to claim 2 wherein driving means comprises an electromagnet, said driving means and switch means comprising a relay.

4. The construction according to claim 1 wherein a pair of flexible contact carrying arms are provided on opposite sides of said movable contact arm, said movable contact being normally engaged with one stationary contact and movable by said driving means to engage the other stationary contact, and means for limiting the flexure of said added stationary contact arm under impact.

5. The construction according to claim 1 wherein a pair of flexible contact carrying arms are provided on opposite sides of said movable contact arm, said movable contact being normally engaged with one stationary contact and movable by said driving means to engage the other stationary contact and rigid stationary arms for limiting the flexure of said stationary contact carrying arms.

6. A relay comprising an electromagnet, an armature for said electromagnet movable in response to energization of said electromagnet from a normal deenergized position, a movable contact arm carried at one end of said armature, movable contacts on opposite sides of said movable contact arm, a stack having at least two stationary contact arms, each stationary contact arm having a stationary contact at the end thereof, said stationary contacts being disposed on opposite sides of said movable contacts for cooperation therewith, means for limiting the movement of each stationary contact arm in response to contact closure and an insulating strip in said stack extending between the flexing portions of said stationary contact arms for limiting the movement of said stationary contact arms toward each other.

7. The relay according to claim 6 wherein said two stationary contact arms are normally spaced so that when untensioned the movable contacts will engage both of the stationary contacts simultaneously, a movable contact engaging only one stationary contact in the extreme position of the movable contacts.

8. An electric switch comprising a flexible stationary contact arm carrying a contact, a flexible movable contact arm carrying a contact and adapted to move the contact carried thereby into and out of contact with said contact on said stationary contact arm, means for driving the movable arm sufiiciently hard to flex and maintain flexed the stationary arm when contact is made, and stop means contacting the flexing portion of said stationary contact arm to abruptly halt the following action of said stationary contact arm tending to move with said movable contact arm as the movable contact arm is moved in the contact-breaking direction to thereby provide a quick breaking action.

9. An electric switch according to claim 8 in which said flexible stationary contact arm is biased to bear against said stop means when said switch is open.

References Cited in the file of this patent UNITED STATES PATENTS 255,378 Connolly Mar. 21, 1882 1,947,641 Broekhuysen Feb. 20, 1934 2,172,202 Johnson Sept. 5, 1939 2,315,920 Baker et al. Apr. 6, 1943 2,321,834 Marco et al June 15, 1943 2,339,610 Baker Jan. 18, 1944 2,398,657 McMaster et a1. Apr. 16, 1946 2,421,642 Obszarny June 3, 1947 2,423,524 Side July 4, 1947 2,490,280 Rees Dec. 6, 1949 2,636,094 Russell Apr. 21, 1953 2,769,881 Hailes Nov. 6, 1956 

